nesdev.com

Hah, I love this. That way you can have it match the very color your NES displayed (assuming you had one back in the day).



I've noticed that the Game Genie uses gray as the background color when starting the original code.



This can't be true, otherwise you could claim that a particular NES is inaccurate because it has one particular instead of the others. Maybe an uncollapsed quantum wave function of a NES would satisfy this. :)

As for the palette values at power-up, we've established that they are not consistent on different NES units, that none of 3500+ games rely on the initial values, and that being dynamic RAM, the first entry might start out as 0x0f. Each emulator author can make his own decision as to what is "best", but it's silly to try to have everyone here agree on something subjective (that being what tradeoffs to make between accuracy and enhancement).

I just realized that you don't need to keep a flag for each palette entry, just a second "rendering" palette that you use for actual rendering but that the emulated code can never read from. At power-up, fill this palette with black ($0f) and fill the normal palette with whatever accurate power-up values you're using. Then when you have a palette write, write to both palettes. This way black is used until a particular palette entry is first written, then its normal color is used. The change is very minimal: